While a significant number of people have dental conditions that require replacement prostheses (e.g., crowns), many of these people elect not to have dental prostheses work performed because such work is traditionally costly, time consuming, and sometimes ineffective. In particular, conventional dental practice methods require that a person make at least two separate visits to a dentist for replacement prostheses work—typically a first visit for diagnosis, planning and preparation work, and a second visit for installation and fitting. The person may also be required to wear a temporary prosthesis between visits.
At the first visit, diagnostic work is performed to determine, with the patient's approval, a choice and method for treatment. In the context of a replacement prosthesis being a crown, for example, the diagnostic work often includes taking diagnostic impressions (e.g., a wax mold) of the patient's teeth for a diagnostic study of the patient's dentition. Next, the patient's tooth structure is modified in preparation to “fit” a crown. For example, the tooth that is to receive the crown is reduced in size such that the crown will “fit” on the tooth and within the patient's dentition.
A physical dental impression of the prepared tooth is taken, and a temporary crown is placed over the tooth. The dental impression is sent to a dental laboratory (usually offsite), where technicians manually design a final crown based on the dentist's prescription and the patient's physical dental impression. Typically, the final crown design is performed manually on cast stones, which is a physically labor-intensive practice that can introduce errors into the final crown. The final crown is then manufactured and sent to the dentist. With the final crown ready, the patient is recalled for the second visit, which may be scheduled days or even weeks after the first visit.
At the second visit, the temporary crown is removed, and the final crown is fitted, adjusted, and cemented into place. If for some reason the final crown does not fit properly, the patient may be required to repeat the preparation process described above and return at a later date for yet another visit. It has been found that a significant number of crowns manufactured using the above-described traditional techniques do not fit properly at the first installation, and thereby lead to repeat visits. As can be seen, traditional restoration treatment processes are long and time-consuming for both the patient and the dentist.
Traditional dental restoration procedures also suffer from additional shortcomings. For example, conventional procedures for taking physical dental impressions and designing restoration prostheses from the physical impressions are prone to distortions that can affect the final fit of restoration prostheses. These distortions can be caused by numerous factors, including technique, temperature, manual handling, technician or dentist error, patient movement, material properties and age, or salivary contamination.
Further, conventional procedures for designing restoration prostheses from physical dental impressions are labor intensive, time consuming, and costly. Prostheses are usually designed and fabricated offsite, which requires transport arrangements, costs, and time. As mentioned above, a patient may be required to wait significant amounts of time before returning to the dentist to have restoration prostheses fitted and installed. In sum, traditional dental restoration procedures are inefficient, error-prone, time consuming, labor intensive, and costly.